Issue with regex

[6en6ar]

Describe the bug
A clear and concise description of what the bug is.
The regex on line 10. is vulnerable to regex denial of service when provided with malicious input.

To Reproduce
I tested it on the isValidSync() function by feeding a malformed input. The program hangs for indefinite amount of time when provided this input. Here is the source code.

`
const emailCheck = require('node-email-check');

//payload
var chck = emailCheck.isValidSync('-@[IPv6:5:3:2:3:227IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"IPv6"');
//var chck = emailCheck.isValidSync('validemail@example.com');
console.log(chck);
console.timeEnd('[ + ] Time passed -> ');
`

Expected behavior
Usually these kind of attack are returning with a small difference in time but this time the function hangs. This bug leads to denial of service.

Additional context
Add any other context about the problem here.